Mussel shell mulch can increase vineyard sustainability by changing scarab pest behaviour

Abstract

Global concern about external costs of pesticides (environment and human health) has promoted the development of new strategies for pest control in agro-ecosystems. In this sense, mineral-based dust and optical barriers have been used against agricultural pests in a variety of crops worldwide as alternatives to orthodox pest control. Recently, mussel shells’ optical properties have been investigated, suggesting their potential role in pest control as an optical barrier. In the present study, the effects of hydrophobic particle films, diatomaceous earths and mussel shells were evaluated for their potential in reducing the endemic New Zealand scarab Costelytra zealandica damage in vineyards. Feeding deterrents significantly reduced its damage by 46% when applied to Pinot Noir vines. In addition, vines treated with mussel shells had 69% fewer beetles on them. When hydrophobic particle films and mussel shells were evaluated in the same experiment, 33 and 73% reduction in damage was achieved by these two treatments, respectively. Furthermore, the addition of mussel shells increased grape yield by 28%. Here we demonstrate that mussel shells applied in the under-vine areas altered the flying and landing behaviour of a melolonthine pest. This is the first reported example of “waste” mollusc shells changing insect pest behaviour, highlighting their potential use in sustainable pest control programmes. Therefore, this approach might contribute to reducing the damage caused by other Scarabaeidae beetles with similar flight behaviour around the world.